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CALCIUM HYDROXIDE PROCESS
Austrian National Library, Vienna, Austria
Otto Wachter, Inventor, Scientist
Otto Wachter developed an aqueous combined deacidification and strengthening process for the preservation of bound newspapers in the collections of the Austrian National Library. The process involves removing the bindings, washing the text block with warm water, draining, permeation by a solution of calcium hydroxide (to provide deacidification) and methyl cellulose (to provide strengthening). The treated text blocks are drained, frozen solid, and the frozen water removed by sublimation (freeze drying). Covers are then reattached to the dried text blocks. The process as now operated can deacidify 56 books a week. The Library is planning to increase capacity with additional freezers.
- The process does not appear to have application for the mass
treatment of library collections.
ETHYLENE OXIDE-AMMONIA PROCESS (BPA)
Book Preservation Associates, Inc., Linden,
Dr. Michael Howe, President
Dr. Michael Howe, inventor of the process, is President of Book Preservation Associates. He is also part owner and President of Sterilization, Inc. Book Preservation Associates was formed by Dr. Howe to provide deacidification services. Book Preservation Associates does not have facilities of its own but uses the resources of Sterilization Inc. The book deacidification tests were conducted, in part, at the medical products sterilization facilities, COSMED II, in Coventry, R.I.
Dr. Howe's BPA deacidification process uses ethylene oxide and ammonia in gas phase to neutralize acid in book paper. Ethylene oxide sterilization chambers were modified to allow the introduction of ammonia at the appropriate point of the deacidification process. There was relatively good success neutralizing the acids in book paper, but laboratory analysis showed lack of stability. The processed paper returned to an acidic state after artificial aging.
There have, according to Dr. Howe, been some promising results with his deacidification process. There are the advantages of gas phase technology, and the process is limited in the quantity of books it can handle only by the size of the chamber. Some of the sterilization chambers are able to accommodate a trailer-truck load of medical products at one time.
A major challenge to the process is that ethylene oxide is considered a carcinogen. Its use for preserving books is very problematic because of the potential for residual ethylene oxide in the processed books. Dr. Howe recognizes the difficulty of developing sufficient data to remove doubt about toxicological safety. He has no plans to do toxicological safety studies, since that work is beyond his resources.
The safety concerns associated with ethylene oxide (ETO) are well known to iibraries. In the past, most large libraries used the chemical in-house to funigate books. virtually all ETO chambers have been taken out of use because of concern for toxicological safety.
- Efficacy of the process is questionable because of the instability of the neutralization.
- There is low residual alkaline reserve.
Demonstrating toxicological safety appears to be a major challenge. - It is known to cause color formation from the reaction of ammonia.
- The BPA process will not be useful unless the toxicological issue is resolved.
MAGNESIUM OXIDE PROCESS (BOOKKEEPER)
SUPPLIER: Preservation Technologies, Inc., Glenshaw,
Richard Spatz, President
Dr. Edward W. Kifer, Vice President
Richard Spatz was President of the Wood Products Chemical Specialties Division, Koppers Chemicals when he learned about the need for a method to deacidify the paper in books. He oversaw the development of a process invented in 1981 by Robert A. Kundrot. The deacidification process is based on the use of submicron size magnesium oxide particles in suspension in chlorofluorocarbon (freon). Whole books are immersed in the chemical, spine down and agitated to allow complete penetration. The magnesium oxide particles are deposited at the fiber level inside and on the surface of the paper.
The Bookkeeper Process was developed to a six book per batch process level some years ago but for a variety of reasons it has not been developed further. A new partnership has been formed with a chemist Dr. Edward Kifer and a coatings manufacturer, Randall L. Russell. The State of Pennsylvania recently approved a "Benjamin Franklin Grant" to help develop the process.
There are outstanding questions as to the efficacy of the process. The magnesium oxide deposited on the paper fibers provides an alkaline reserve in the paper but it is not clear that the acid in the paper is neutralized in the absence of water hydrolysis of the magnesium oxide. Very little data is published on the process and much work needs to be done.
Uniform delivery of the magnesium oxide to the paper in the books depends on agitation to open the pages of the books and to keep the oxide in uniform suspension. In addition, the process uses chlorofluorocarbons as a vehicle to deliver the alkalizing agent and it will be essential to close the system to the atmosphere and recover the solvent. These are major engineering challenges.